Parasites Worms

Blastocystis hominis is a common protozoan parasite found in the intestines and often identified in individuals with gastrointestinal symptoms. Although its role in causing illness is still debated, it is frequently associated with various digestive problems and is commonly detected in stool tests worldwide.

Cryptosporidium spp. are a group of protozoan parasites that cause cryptosporidiosis, an infectious gastrointestinal disease. Known for their resilience in various environments, especially in water, these parasites play a crucial role in outbreaks of diarrheal illness affecting both humans and animals.

Cyclospora cayetanensis is a microscopic protozoan parasite that causes cyclosporiasis, an intestinal infection characterized by prolonged and recurrent diarrhoea. It is commonly found in tropical and subtropical regions and has been associated with numerous foodborne outbreaks worldwide.

Dientamoeba fragilis is a unicellular parasite found in the human gastrointestinal tract. It is associated with dientamoebiasis, a condition that can cause a range of digestive symptoms. Its precise method of transmission and its role in causing disease are still being studied.

Dwarf tapeworms (Hymenolepis nana) are common parasites that infect humans, especially children. They are unique as they can complete their entire life cycle within a single host, enabling direct transmission without the need for an intermediate host. Although infections are often asymptomatic, they can cause abdominal pain, diarrhoea, and in severe cases, weight loss and malnutrition.

Entamoeba histolytica is a protozoan parasite responsible for amoebiasis, an infection that can range from mild or asymptomatic to severe forms, including dysentery and liver abscesses. It is a major public health concern in regions with poor sanitation, particularly in tropical and subtropical countries.

Enterocytozoon and Encephalitozoon species are microsporidia — spore-forming unicellular parasites that can infect humans. They can cause gastrointestinal and systemic diseases, particularly in people with weakened immune systems. Symptoms depend on the infection site but commonly include diarrhea, weight loss, and fatigue.

Flatworms and tapeworms are parasitic worms that can infect the human digestive tract, most commonly through the consumption of undercooked or contaminated meat. Tapeworms belong to the class Cestoda and can grow several meters long inside the intestines. Once inside the host, they attach to the intestinal wall and absorb nutrients, often leading to symptoms such as digestive issues, weight loss, or fatigue. In many cases, however, the infection can be asymptomatic and go undetected for long periods. Diagnosis typically involves stool sample analysis to detect eggs or worm segments.

Giardia lamblia is a protozoan parasite that causes giardiasis, an intestinal infection characterized by diarrhea and digestive discomfort. Known for its durability, it can survive in tough conditions, especially contaminated water, making it a frequent cause of waterborne outbreaks.

Hookworms are parasitic worms that reside in the small intestine and feed on the host’s blood. They are commonly found in areas with poor sanitation and can cause anaemia, protein deficiency, abdominal pain, diarrhoea, and fatigue. Infection usually occurs through skin contact with soil contaminated with hookworm larvae.

Microsporidia are a group of microscopic, spore-forming parasites that primarily infect the intestinal tract but can also affect the eyes, muscles, and other organs, especially in individuals with weakened immune systems. These organisms are classified as fungi or fungus-like and are known to cause a condition called microsporidiosis. Transmission typically occurs through ingestion of contaminated food or water, or contact with infected animals or surfaces. Symptoms can include chronic diarrhea, weight loss, fatigue, and abdominal discomfort.

New World hookworms (Necator americanus) are parasitic worms commonly found in the Americas. These parasites attach themselves to the walls of the intestines in their hosts, causing chronic blood loss, anaemia, and protein deficiency. The larvae can penetrate the skin when individuals come into contact with contaminated soil, putting them at risk of infection.

Pinworms (Oxyuris), also known as threadworms, are common intestinal parasites, especially in children. These small, white worms cause itching around the anus, disturbed sleep, and irritability due to laying eggs at night. Infection spreads through the faecal-oral route, often by swallowing microscopic eggs from contaminated hands, surfaces, or food.

Roundworms are parasitic nematodes that can infect the human digestive system, typically causing symptoms such as abdominal pain, diarrhoea, and discomfort. Transmission often occurs through contaminated soil, water, or undercooked food. If left untreated, infections can lead to more serious health complications.

Tapeworms are intestinal parasites that can affect both humans and animals. These flat, segmented worms can grow to significant lengths. They usually enter the body through the consumption of contaminated food or water. While tapeworm infections may sometimes show no symptoms, they can also cause stomach discomfort, diarrhea, and weight loss.

Threadworms (Strongyloides stercoralis) are tiny intestinal parasites that cause strongyloidiasis. They may not show symptoms or can cause a range of issues, including stomach pain, diarrhea, and in severe cases, malabsorption. Transmission happens when skin comes into contact with contaminated soil. These worms are unique because they can reproduce inside the host, leading to persistent, long-term infections.

Whipworms (Trichuris trichiura) are intestinal parasites named for their distinctive whip-like shape. Infection occurs through ingestion of eggs present in soil contaminated with human feces. While many cases are symptom-free, heavy infestations can cause diarrhea, abdominal pain, and in severe cases, rectal prolapse. Children are especially vulnerable, as chronic infections may impact growth and cognitive development.